Most encryption algorithms are designed without regard to their performance on top-of-the-line microprocessors. This paper discusses general optimization principles algorithms designers should keep in mind when designing algorithms, and analyzes the performance of RC4, SEAL, RC5, Blowfish, and Khufu/Khafre on the Intel Pentium with respect to those principles. Finally, we suggest directions for algorithm design, and give example algorithms, that take performance into account.

This paper describes the CAST design procedure for constructing a family of DES-like Substitution-Permutation Network (SPN) cryptosystems which appear to have good resistance to differential cryptanalysis, linear cryptanalysis, and related-key cryptanalysis, along with a number of other desirable cryptographic properties. Details of the design choices in the procedure are given, including those regarding the component substitution boxes (s-boxes), the overall framework, the key schedule, and the round function. An example CAST cipher, an output of this design procedure, is presented as an aid to understanding the concepts and to encourage detailed analysis by the cryptologic community.

Linear cryptanalysis and differential cryptanalysis are two recently introduced, powerful methodologies for attacking private-key block ciphers. In this paper, we examine the application of these two cryptanalysis techniques to a CAST-like encryption algorithm based on randomly generated s-boxes. It is shown that, when randomly generated substitution boxes (s-boxes) are used in a CAST-like algorithm, the resulting cipher is resistant to both the linear attack and the differential attack. 1 Introduction As the need for privacy and authentication is now generally recognized by the telecommunications community, a widely adopted private-key encryption algorithm is becoming an increasingly important objective in the development and analysis of cryptographic algorithms. For some time, the Data Encryption Standard (DES) [16] has been the most widely used and trusted encryption algorithm. However, DES is about twenty years old and has recently become vulnerable to cryptanalysis due to its smal...

1.4 Simple XOR

Abstract We propose a new attack on Feistel ciphers with a non-surjective round function. CAST and LOKI91 are examples of such ciphers. We extend the attack towards ciphers that use a non--uniformly distributed round function and apply the attack to CAST. 1 Introduction The Feistel structure is a very common structure for block ciphers, the most prominent example being the Data Encryption Standard [FI46]. Although DES has been a worldwide de facto standard since 1977, everybody agrees that it is reaching the end of its life time. The main reason is the size of the key, which is only 56 bits. The key size was already a topic of discussion in the seventies [DH77], and it was shown recently by M. Wiener that at present an exhaustive key search in 3.5 hours requires only 1 million US$ of equipment [W93]. Of more theoretical interest are recent cryptanalytic techniques such as differential [BS93] and linear [Ma93a, Ma94] cryptanalysis which provide techniques to recover the key faster tha...

Problem statement: This paper examines Artificial Spiking Neural Network (ASNN) which inter-connects group of artificial neurons that uses a mathematical model with the aid of block cipher. The aim of undertaken this research is to come up with a block cipher where by the keys are randomly generated by ASNN which can then have any variable block length. This will show the private key is kept and do not have to be exchange to the other side of the communication channel so it present a more secure procedure of key scheduling. The process enables for a faster change in encryption keys and a network level encryption to be implemented at a high speed without the headache of factorization. Approach: The block cipher is converted in public cryptosystem and had a low level of vulnerability to attack from brute, and moreover can able to defend against linear attacks since the Artificial Neural Networks (ANN) architecture convey non-linearity to the encryption/decryption procedures. Result: In this paper is present to use the Spiking Neural Networks (SNNs) with spiking neurons as its basic unit. The timing for the SNNs is considered and the output is encoded in 1’s and 0’s depending on the occurrence or not occurrence of spikes as well as the spiking neural networks use a sign function as activation function, and present the weights and the filter coefficients to be adjust, having more degrees of freedom than the classical neural